Journal Publication

Brensocatib subgroup data show consistent effect in Asian ASPEN patients

A subgroup analysis of the ASPEN trial found brensocatib cut pulmonary exacerbations by about 60% in 191 Asian participants, in line with the overall study population.

A prespecified subgroup analysis of the ASPEN trial reported that brensocatib reduced pulmonary exacerbations and, at the 25 mg dose, slowed lung-function decline in 191 participants of Asian race with non-cystic fibrosis bronchiectasis.

By AppliedXLJuly 16, 2026Trial NCT04594369

Executive Summary

A prespecified subgroup analysis from the completed Phase 3 ASPEN trial asked whether brensocatib's effect on pulmonary exacerbations held in participants of Asian race, a population that made up roughly a tenth of the overall study.
Both drug doses reduced exacerbation risk and prolonged time to first exacerbation in this subgroup, and the higher dose also slowed lung-function decline and improved patient-reported symptoms, tracking the effect already established in the trial's full population.
The analysis reinforces that the drug's benefit is not concentrated in or dependent on any single racial group, though the trial was not built to formally test for subgroup differences.
The result lands in a bronchiectasis treatment field where this mechanism is already established as the first approved therapy, with several other DPP1 inhibitors still in earlier-stage development behind it.

The finding

The analysis, published July 16, 2026, examined outcomes for 191 participants of Asian race enrolled in ASPEN (NCT04594369), split roughly evenly across brensocatib 10 mg, brensocatib 25 mg, and placebo arms. Both active doses significantly reduced the annualized rate of pulmonary exacerbations by approximately 60% versus placebo, with p-values of 0.0005 for the 10 mg dose and 0.0012 for the 25 mg dose. Both doses also prolonged the time to first exacerbation, cutting the hazard by roughly 55% (p=0.0039 and p=0.0082, respectively). NCT04594369+1

How it was done

ASPEN was a randomized, double-blind, placebo-controlled Phase 3 trial that enrolled 1,767 participants across the United States, Japan, and Argentina, with adults dosed once daily for 52 weeks in a 1:1:1 allocation and adolescents in a 2:2:1 allocation. The primary endpoint was the annualized rate of adjudicated pulmonary exacerbations through Week 52, with secondary endpoints covering time to first exacerbation, change in postbronchodilator FEV1, and the QOL-B respiratory symptoms score. This subgroup analysis was prespecified and examined the 191 Asian-race participants within that same trial population and endpoint structure. NCT04594369+1

The secondary results

In the 25 mg arm, the drug also produced a least-squares mean difference of 69 mL versus placebo in postbronchodilator FEV1 decline at Week 52 (95% CI 24-114 mL, p=0.0029) and a 7.49-point improvement on the QOL-B respiratory symptoms domain (95% CI 2.48-12.50, p=0.0034). These secondary measures moved together with the primary exacerbation result in the same dose arm, suggesting the drug's benefit extended beyond exacerbation counts into lung function and patient-reported symptoms for participants on the higher dose. Efficacy

Safety and context

The frequency of treatment-emergent adverse events in the Asian subgroup was similar across treatment arms and consistent with the safety profile reported for the overall ASPEN population. The trial's own authors caution that ASPEN was not powered to detect treatment differences in prespecified subgroup analyses, so the subgroup's numerically larger effect sizes should be read as consistent with, rather than distinct from, the trial's overall result. Efficacy

The mechanism's place

Brensocatib, a dipeptidyl peptidase 1 inhibitor, holds FDA approval as BRINSUPRI for non-cystic fibrosis bronchiectasis in patients 12 and older, making it the first approved treatment built on this mechanism in the indication. Other DPP1 inhibitors, including Chiesi Farmaceutici's florensocatib, Boehringer Ingelheim's BI 1291583, and Haisco Pharmaceutical's HSK31858, are running their own Phase 3 trials in the same indication, each still working toward the efficacy bar brensocatib's approval already set.

This analysis was produced using AI-assisted reporting systems, AppliedXL data, and official public records. These systems undergo editorial review, quality checks, and regular audits by human experts. Errors may still occur, as with any automated system. Always consult the linked primary sources. Read our AI Editorial Policy.